Methods for improving the recovery of troponin I and T in membranes, filters and vessels
A method to facilitate recovery troponin I and/or troponin T from a sample comprising addition of troponin C to the sample or to a surface from which the troponin I and/or troponin T are recovered.
1. A method for diagnosing heart muscle damage, comprising:
performing an immunoassay to determine the amount of cardiac troponin I in a sample from a subject, by combining
a) an antibody conjugate comprising a signal generating element and a first antibody that specifically binds to cardiac troponin I complexed with troponin C and troponin T and specifically binds to free cardiac troponin I; and
b) said sample, thereby forming a reaction mixture comprising said antibody conjugate bound to said cardiac troponin I, if present, in said sample;
applying said reaction mixture to a surface comprising a second antibody capable of specifically binding to cardiac troponin I;
capturing said cardiac troponin I—antibody conjugate complex on said surface via said second antibody, whereby the captured complex produces a detectable signal;
detecting said signal;
relating said signal to the amount of troponin I present in the sample, wherein said immunoassay is configured to provide assay results that are within a factor of two for (i) cardiac troponin I, uncomplexed to either troponin T or troponin C; and (ii) an equivalent concentration of cardiac troponin I in a complex with troponin T and troponin C and;
relating the amount of cardiac troponin I present in the sample to the occurrence or nonoccurrence of heart muscle damage.
2. The method of claim 1 , wherein said sample is whole blood, plasma or serum.
3. The method of claim 1 , wherein said first antibody yields an assay response for oxidized cardiac troponin I, reduced cardiac troponin I and cardiac troponin I in complex with troponin C and troponin T that is within 20% of an assay response for an equivalent concentration of oxidized cardiac troponin I alone, reduced troponin I alone, and said complexed troponin I alone.
4. The method of claim 1 , wherein said first antibody, said second antibody, or both, is a monoclonal antibody.
5. The method of claim 1 , wherein said second antibody specifically binds to cardiac troponin I complexed with troponin C and troponin T and specifically binds to free cardiac troponin I.
6. The method of claim 1 , 2 , 3 , 4 or 5 , wherein the heart muscle damage is myocardial infarction.